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1.
J Hazard Mater ; 441: 129869, 2023 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-36063709

RESUMO

The first synthetic review of the PAHs effects on microalgae in experimental studies and aquatic ecosystems is provided. Phytoplankton and phytobenthos from marine and freshwaters show a wide range of sensitivities to PAHs, and can accumulate, transfer and degrade PAHs. Different toxicological endpoints including growth, chlorophyll a, in vivo fluorescence yield, membrane integrity, lipid content, anti-oxidant responses and gene expression are reported for both freshwater and marine microalgal species exposed to PAHs in culture and in natural assemblages. Photosynthesis, the key process carried out by microalgae appears to be the most impacted by PAH exposure. The effect of PAHs is both dose- and species-dependent and influenced by environmental factors such as UV radiation, temperature, and salinity. Under natural conditions, PAHs are typically present in mixtures and the toxic effects induced by single PAHs are not necessarily extrapolated to mixtures. Natural microalgal communities appear more sensitive to PAH contamination than microalgae in monospecific culture. To further refine the ecological risks linked to PAH exposure, species-sensitivity distributions (SSD) were analyzed based on published EC50s (half-maximal effective concentrations during exposure). HC5 (harmful concentration for 5% of the species assessed) was derived from SSD to provide a toxicity ranking for each of nine PAHs. The most water-soluble PAHs naphthalene (HC5 = 650 µg/L), acenaphthene (HC5 = 274 µg/L), and fluorene (HC5 = 76.8 µg/L) are the least toxic to microalgae, whereas benzo[a]pyrene (HC5 = 0.834 µg/L) appeared as the more toxic. No relationship between EC50 and cell biovolume was established, which does not support assumptions that larger microalgal cells are less sensitive to PAHs, and calls for further experimental evidence. The global PAHs HC5 for marine species was on average higher than for freshwater species (26.3 and 1.09 µg/L, respectively), suggesting a greater tolerance of marine phytoplankton towards PAHs. Nevertheless, an important number of experimental exposure concentrations and reported toxicity thresholds are above known PAHs solubility in water. The precise and accurate assessment of PAHs toxicity to microalgae will continue to benefit from more rigorously designed experimental studies, including control of exposure duration and biometric data on test microalgae.


Assuntos
Microalgas , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Acenaftenos/metabolismo , Acenaftenos/farmacologia , Antioxidantes/metabolismo , Benzo(a)pireno/metabolismo , Clorofila A , Ecossistema , Fluorenos/metabolismo , Água Doce , Lipídeos , Fitoplâncton , Hidrocarbonetos Policíclicos Aromáticos/análise , Água/farmacologia , Poluentes Químicos da Água/metabolismo
2.
J Hazard Mater ; 441: 129921, 2023 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-36103767

RESUMO

Glyphosate will be banned from Europe by the end of 2022, but its widespread use in the last decades and its persistence in the environment require the development of novel remediation processes. In this work, a bacterial consortium was designed de novo with the aim to remove glyphosate from polluted water, supported by the oxygen produced by a microalgal species. To this goal, bioinformatics tools were employed to identify the bacterial strains from contaminated sources (Pseudomonas stutzeri; Comamonas odontotermitis; Sinomonas atrocyanea) able to express enzymes for glyphosate degradation, while the microalga Chlorella protothecoides was chosen for its known performances in wastewater treatment. To follow a bioaugmentation approach, the designed consortium was cultivated in continuous photobioreactors at increasing glyphosate concentrations, from 5 to 50 mg L-1, to boost its acclimation to the presence of the herbicide and its capacity to remove it from water. C. protothecoides tolerance to glyphosate was verified through batch experiments. Remarkably, steady state conditions were reached and the consortium was able to live as a community in the reactor. The consortium activity was validated in both synthetic and real wastewater, where glyphosate concentration was reduced by about 53% and 79%, respectively, without the detection of aminomethylphosphonic acid formation.


Assuntos
Chlorella , Herbicidas , Microalgas , Bactérias/metabolismo , Biodegradação Ambiental , Chlorella/metabolismo , Glicina/análogos & derivados , Herbicidas/metabolismo , Microalgas/metabolismo , Oxigênio/metabolismo , Fotobiorreatores/microbiologia , Águas Residuárias , Água
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 284: 121791, 2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36057160

RESUMO

Microalgae have been reputed as novel biological materials due to their unique structure, surface functionality and optical activity, making them worthwhile agents in biosensing and theranostic applications. However, further scrutiny is required for utilizing them in routine optical techniques due to their complex structure and diverse chemical components. Here, laser induced fluorescence (LIF) features of a bio-compatible microalgae i. e. Arthrospira platensis (Spirulina) have been assessed. Typical fluorescence properties as well as the inner filter effects (IFEs) were examined and revealed to be strongly dependent on concentration, excitation wavelength, and detection geometry as well. IFEs and resulting spectral shifts have been analyzed considering various SP chromophores, reabsorption processes, and resonance energy transfer (RET) mainly from "Carotenoids to Phycobilisomes" as well as "Phycobilisomes to Chlorophyll-a". As a result, LIF spectral shift due to the re-absorption events (secondary-IFE) is introduced as a credible parameter for design of precise fluorescence-based sensors, due to being less dependent on ambient noises. We hope that the findings provide novel features regarding the LIF of Spirulina (SP) that could be utilized to design and develop optical sensors in the field of photonics, material diagnosis and biomedical theranostics.


Assuntos
Microalgas , Spirulina , Carotenoides , Clorofila/química , Ficobilissomas , Spirulina/química
4.
Food Chem ; 403: 134348, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36166925

RESUMO

The marine carotenoid fucoxanthin (FX) has various health benefits but suffers from poor bioavailability. We hypothesize that the bioavailability of FX in microalga Phaeodactylum tricornutum extract (PE) could be improved through nanoencapsulation. Here, we developed two types of nanoparticles: one consisting of alginate and casein (A-C-PE, 246 nm diameter, 79.6% encapsulation efficiency) and the other A-C-PE coated with chitosan (CS-A-C-PE, 258 nm, 78.1%). Both types of nanoparticles incorporating PE showed controlled FX release during simulated gastrointestinal digestion, as well as 1.8-fold improvement of membrane permeability in Caco-2/TC7 cells compared to non-encapsulated PE. Pharmacokinetic behavior of two FX metabolites (fucoxanthinol and amarouciaxanthin A) in mouse plasma was monitored after oral administration. The results showed that 31.8-332.1% more FX metabolites from the nanoparticles were absorbed into plasma than those from PE. In conclusion, encapsulation of PE in both types of nanoparticles significantly promoted the bioavailability of FX.


Assuntos
Microalgas , Humanos , Camundongos , Animais , Disponibilidade Biológica , Microalgas/metabolismo , Células CACO-2 , Xantofilas/metabolismo
5.
J Hazard Mater ; 443(Pt A): 130201, 2023 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-36283215

RESUMO

The comprehensive effect of exogenous pollutants on the dispersal and abundance of antibiotic-resistance genes (ARGs) in the phycosphere, bacterial community and algae-bacteria interaction remains poorly understood. We investigated community structure and abundance of ARGs in free-living (FL) and particle-attached (PA) bacteria in the phycosphere under nanoparticles (silver nanoparticles (AgNPs) and hematite nanoparticles (HemNPs)) and antibiotics (tetracycline and sulfadiazine) stress using high-throughput sequencing and real-time quantitative PCR. Meanwhile, the intrinsic connection of algae-bacteria interaction was explored by transcriptome and metabolome. The results showed that the relative abundance of sulfonamide and tetracycline ARGs in PA and FL bacteria increased 103-129 % and 112-134 %, respectively, under combined stress of nanoparticles and antibiotics. Antibiotics have a greater effect on ARGs than nanoparticles at environmentally relevant concentrations. Proteobacteria, Firmicutes, and Bacteroidetes, as the primary potential hosts of ARGs, were the dominant phyla. Lifestyle, i.e., PA and FL, significantly determined the abundance of ARGs and bacterial communities. Moreover, algae can provide bacteria with nutrients (carbohydrates and amino acids), and can also produce antibacterial substances (fatty acids). This algal-bacterial interaction may indirectly affect the distribution and abundance of ARGs. These findings provide new insights into the distribution and dispersal of ARGs in microalgae-bacteria symbiotic systems.


Assuntos
Nanopartículas Metálicas , Microalgas , Antibacterianos/farmacologia , Antibacterianos/análise , Microalgas/genética , Genes Bacterianos , Prata/toxicidade , Bactérias/genética , Resistência Microbiana a Medicamentos/genética , Tetraciclinas
6.
J Hazard Mater ; 443(Pt A): 130213, 2023 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-36283219

RESUMO

Pharmaceutical compounds in aquatic environments have been considered as emerging contaminants due to their potential risks to living organisms. Microalgae-based technology showed the feasibility of removing pharmaceutical contaminants. This review summarizes the occurrence, classification, possible emission sources, and environmental risk of frequently detected pharmaceutical compounds in aqueous environments. The efficiency, mechanisms, and influencing factors for the removal of pharmaceutical compounds through microalgae-based technology are further discussed. Pharmaceutical compounds frequently detected in aqueous environments include antibiotics, hormones, analgesic and non-steroidal anti-inflammatory drugs (NSAIDs), cardiovascular agents, central nervous system drugs (CNS), antipsychotics, and antidepressants, with a concentration ranging from ng/L to µg/L. Microalgae-based technology majorly remove the pharmaceutical compounds through bioadsorption, bioaccumulation, biodegradation, photodegradation, and co-metabolism. This review identifies the opportunities and challenges for microalgae-based technology and proposed suggestions for future studies to tackle challenges. The findings of this review advance our understanding of the occurrence and fate of pharmaceutical contaminants in aqueous environments, highlighting the potential of microalgae-based technology for pharmaceutical contaminants removal.


Assuntos
Microalgas , Poluentes Químicos da Água , Microalgas/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Biotecnologia , Preparações Farmacêuticas/metabolismo , Águas Residuárias
7.
Chemosphere ; 310: 136808, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36223822

RESUMO

Flame retardants, such as Tetrabromobisphenol A (TBBPA), Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and tributyl phosphate (TBP), are frequently detected in surface water. However, the effects of FRs exposure on aquatic organisms especially freshwater microalgae are still unclear. In this study, the toxicities of TBBPA, TDCPP and TBP to microalgae Chlorella sorokiniana, in terms of growth inhibition, photosynthetic activity inhibition and oxidative damage, were investigated, and according ecological risks were assessed. The results showed that TBBPA, TDCPP and TBP had inhibitory effects on C. sorokiniana, with 96 h EC50 (concentration for 50% of maximal effect) values of 7.606, 41.794 and 49.996 mg/L, respectively. Fv/Fm decreased as the increase of exposure time under 15 mg/L TBBPA. Under 50 mg/L TDCPP and 80 mg/L TBP exposure, Fv/Fm decreased significantly after 24 h. However, Fv/Fm rose after 96 h, indicating that the damaged photosynthetic activity was reversible. The content of chlorophyll a decreased, as the increase of TBBPA concentration from 3 to 15 mg/L. However, chlorophyll a increased first and then decreased, as the increase of TDCPP and TBP concentrations from 0 to 50 mg/L and 0-80 mg/L, respectively. Results indicated that C. sorokiniana could use the phosphorus of TDCPP and TBP to ensure the production of chlorophyll a. The risen content of reactive oxygen species, malondialdehyde as well as superoxide dismutase activity indicated that exposure to FRs induced oxidative stress. Additionally, the risk quotients showed that tested FRs had ecological risks in natural waters or wastewaters. This study provides insights into the toxicological mechanisms of different FRs toward freshwater microalgae for better understanding of according environmental risks.


Assuntos
Chlorella , Retardadores de Chama , Microalgas , Retardadores de Chama/toxicidade , Clorofila A , Compostos Organofosforados/toxicidade , Água Doce
8.
Food Chem ; 401: 134083, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36099816

RESUMO

The impact of Spirulina, Chlorella and Phaeodactylum tricornutum (P. tricornutum) microalgal extracts obtained by pressurized liquid extraction (PLE) on antioxidant and anti-inflammatory activities, microbial growth and in vitro gut microbiota composition was evaluated. PLE, compared to conventional extraction, led to a significant (p < 0.05) increase in proteins, carbohydrates, polyphenols, and antioxidant capacities of the three microalgal extracts. Moreover, Spirulina and P. tricornutum extracts significantly (p < 0.05) reduced the in vitro activation of the inflammatory NF-κB pathway. The microalgal extracts had also an inhibitory effect on the pathogenic bacteria while potential beneficial Lactobacillus and Bifidobacterium strains increased growth. The effects of microalgal extracts on specific bacterial groups were analyzed by quantitative PCR technology, and bacterial gene copy numbers were affected by in vitro digestion process and colonic fermentation time. GC-MS results showed that microalgal biomolecules' digestion promoted the release of short-chain fatty acids (SCFAs) during in vitro colonic microbiota fermentation, particularly acetic, butanoic and propanoic, indicating that the biomolecules in microalgae extracts have potential health benefits for human gut.


Assuntos
Chlorella , Microbioma Gastrointestinal , Microalgas , Spirulina , Humanos , Chlorella/metabolismo , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Spirulina/metabolismo , NF-kappa B/metabolismo , Microalgas/metabolismo , Ácidos Graxos Voláteis/metabolismo , Bactérias/metabolismo , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/metabolismo , Carboidratos
9.
J Colloid Interface Sci ; 629(Pt A): 994-1002, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36152623

RESUMO

Metal sulfides are regarded as efficient scavengers for heavy metals. However, the heavy metal adsorption capacity of metal sulfides is far from its theoretical values due to the insufficient exposure of adsorption sites. Surface modification of metal sulfides is considered one of the most effective strategies for improving heavy metal removal performance. Here, microalgae-derived carbon quantum dots (CQDs) were used as a green modifier for mediating nano-MnS/FeS formation to enhance Cd2+ removal. With the addition of 1 wt% CQDs, the Cd2+ adsorption capacity of 1 %CQDs-MnS reached 481 mg/g at 25 °C and 648.6 mg/g at 45 °C, which surpassed most of the previously reported metal sulfides. Furthermore, the CQDs-modified MnS displayed a better Cd2+ removal capacity than the commercial modifier sodium alginate. The mechanism analysis suggested that decreasing the particle size to expose more adsorption sites and providing additional chelating sites derived from the CQDs are two main reasons why CQDs enhance the Cd2+ adsorption capacity of metal sulfides. This study presents an exceptional cadmium nano-adsorbent of 1 %CQDs-MnS and provides a new perspective on the enhancement of heavy metal removal by using CQDs as a promising and universal green modifier that mediates the formation of metal sulfides.


Assuntos
Metais Pesados , Microalgas , Pontos Quânticos , Cádmio , Carbono , Adsorção , Alginatos , Sulfetos
10.
J Hazard Mater ; 442: 130105, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36206717

RESUMO

Using filamentous fungi to capture unicellular microalgae is an effective way for microalgae recovery in water treatment. Here, fungi Aspergillus flavus ZJ-1 and microalgae Chlorella vulgaris WZ-1 isolated from a copper tailings pond were used to study the capture effect of ZJ-1 on WZ-1. The highest capture efficiency (97.85%) was obtained within 6 h under the optimized conditions of 30 °C, 150 rpm, fungi-algae biomass ratio of 2.24:1, and initial pH of 9.24 in microalgae medium. The formed fungi-algae pellets (FAPs) were further used to remove Cu(II) from aqueous solution. Results showed that the FAPs formed at different capture times all adsorbed Cu(II) well, and the PAFs formed within 2 h (PAFs2 h) exhibited the highest Cu(II) adsorption capacity (80.42 mg·g-1). SEM images showed that Cu(II) caused a change in the internal structure of PAFs2 h from loose to compact, the mycelium shrunk, and the microalgal cells were concave. Cu(II) adsorption by PAFs2 h was well conformed to the pseudo-second-order kinetics and the Langmuir isotherm (123.61 mg·g-1 of theoretically maximum adsorption capacity). This work opens a way for applying FAPs in the remediation of heavy metal-contaminated wastewater, and the metal adsorption effect was determined by the capture amount of microalgae.


Assuntos
Chlorella vulgaris , Microalgas , Poluentes Químicos da Água , Adsorção , Aspergillus flavus , Cobre , Águas Residuárias , Cinética , Fungos , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/química
11.
Methods Mol Biol ; 2581: 123-134, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36413315

RESUMO

Autophagy is a catabolic process by which eukaryotic cells degrade and recycle unnecessary or damaged intracellular components to maintain cellular homeostasis and to cope with stress. The development of specific tools to monitor autophagy in microalgae and plants has been fundamental to investigate this catabolic pathway in photosynthetic organisms. The protein ATG8 is a widely used molecular marker of autophagy in all eukaryotes, including the model microalga Chlamydomonas reinhardtii. The drug concanamycin A, a specific inhibitor of vacuolar ATPase, has also been extensively used to block autophagic flux in the green lineage. In Chlamydomonas, inhibition of autophagic flux by concanamycin A has been shown to prevent the degradation of ribosomal proteins and the formation of lipid bodies under nitrogen or phosphorous starvation. Here, we detail how the abundance and lipidation state of ATG8 can be used to monitor autophagic flux in Chlamydomonas by western blot analysis.


Assuntos
Chlamydomonas reinhardtii , Chlamydomonas , Microalgas , Chlamydomonas reinhardtii/metabolismo , Autofagia/fisiologia , Macrolídeos/farmacologia
12.
Sci Total Environ ; 857(Pt 2): 159461, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36257437

RESUMO

The present study aims to use Ankistrodesmus sp. EHY to develop a viable and economic lipid production strategy using recycling of harvested microalgal effluent. In comparison to the control, the highest lipid content (52.4 %) and productivity (250.72 mg L-1 d-1) were achieved when 40 % recycled medium was used. Consistent with the trend of lipid accumulation, the six key lipogenetic genes were upregulated, as well as reactive oxygen species (ROS), glutathione (GSH) and genes encoding antioxidant enzymes during cultivation in recycled medium. Moreover, the consumption of dissolved organic carbon (DOC) and the increased humic acid (HA) in the recycled medium might also be associated with lipid biosynthesis. The biodiesel parameters of alga biomass-derived lipids were fitted to the standard of commercial biodiesel. In conclusion, this study offers an economically viable strategy for microalgal biofuel production and wastewater treatment using recycling of harvested microalgal effluent.


Assuntos
Clorofíceas , Microalgas , Biocombustíveis , Lipídeos , Biomassa
13.
J Environ Manage ; 325(Pt A): 116452, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36257228

RESUMO

Shrimp farming wastewater includes high amounts of phosphate and microbiological contaminants, necessitating further treatment before release into receiving water bodies. After 24 h of shrimp wastewater treatment, alginate beads containing the blue-green algal Synechocystis strain lacking the phosphate regulator gene (mutant strain ΔSphU) at 150 mg L-1 reduced phosphate content from 17.5 mg L-1 to 5.0 mg L-1, representing 71.5% removal efficiency, with phosphate removal rate reaching 6.9 mg gDW-1 h-1 during photobioreactor operation. For short-term treatment, removal rates of nitrate, ammonium and nitrite were 42.7, 48.5 and 92.9%, respectively. Microalgal encapsulated beads also impacted the bacterial community composition dynamics in shrimp wastewater. Next-generation sequencing targeting the V3-V4 region of the 16S rDNA gene showed significant differences in bacterial community composition after 24 h of treatment. Proteobacteria are the most abundant phylum in shrimp wastewater. After 24 h of bioremediation, reductions of harmful bacteria in the Cellvibrionaceae and Pseudomonadaceae families were recorded at 5.85 and 3.18%, respectively. Engineered microalgal immobilization under optimal conditions can be applied as an alternative short-term bioremediation strategy to remove phosphate and other harmful microbial contamination from shrimp farming wastewater.


Assuntos
Microalgas , Purificação da Água , Humanos , Águas Residuárias/microbiologia , Fosfatos , Bactérias/genética , Biomassa
14.
J Environ Manage ; 325(Pt B): 116582, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36308961

RESUMO

Heterotrophic-assisted photoautotrophic microalgae biofilm cultivation was an alternative way to realize CO2 reduction and wastewater treatment. Growth kinetics supplied a channel to better understand how the cultivation conditions affect microalgal growth and CO2 reduction. However, the two growth modes (heterotroph and photoautotroph) have different needs for organic and inorganic nutrients. Thus, combining the threshold theory and multiplication theory, an integral multifactorial kinetic model that looking insight into the comprehensive effect of glucose, CO2, light intensity, and nitrate was developed for heterotrophic-assisted photoautotrophic microalgae biofilm growth in this study. R2 between model and experiment was 0.99. It predicted the maximum specific growth rate and maximum CO2 consumption rate of heterotrophic-assisted photoautotrophic microalgae biofilm was 1.868 h-1 and 1.02 h-1, respectively. This model fully explained the influence of the main factors on microalgae biofilm growth and reasonably predicted the growth rate of microalgae biofilm under different growth conditions.


Assuntos
Microalgas , Dióxido de Carbono/farmacologia , Glucose/farmacologia , Cinética , Biofilmes , Biomassa
15.
Bioresour Technol ; 367: 128239, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36332861

RESUMO

Microalgae are considered an efficient accumulator and promising source of Se for feed additive purposes. This study aimed at investigating, for the first time, the effect of phosphorus limitation on Se accumulation and uptake efficiency in N.oceanica. A range of phosphorus concentrations (0-2470 µM) were tested in either the presence or absence of sodium selenite (0, 5, 30 µM). Se accumulation was increased up to 16-fold and Se uptake efficiency was increased up to 3.6-fold under phosphorus growth-limiting concentrations. N.oceanica was then cultivated in a 1.8L flat-panel photobioreactor in batch operation under two phosphorus growth-limiting concentrations (250 and 750 µM) where the accumulation of Se in the microalgal biomass, as well as its presence in the spent medium were analysed. This study is the first to investigate the effect of phosphorus limitation for increasing Se accumulation in microalgae, and to prevent the release of Se in wastewater.


Assuntos
Microalgas , Estramenópilas , Fósforo/farmacologia , Fotobiorreatores , Biomassa
16.
Bioresour Technol ; 367: 128304, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36370947

RESUMO

Microalgae-bacteria symbiosis system (MBS) appear to be a promising way for treating the rare earth elements (REEs) wastewater due to the natural symbiotic interactions between microalgae and bacteria. Herein, we investigated the effect of different inoculation ratios of microalgae and bacteria including 3:1 (MB_1), 1:1 (MB_2) and 1:3 (MB_3) on NH4+-N removal from REEs wastewater and analyzed the corresponding biological mechanism. The NH4+-N removal rate with MB_3 reached 17.69 ± 0.45 mg NH4+-N/L d-1, which was 2.58 times higher than that in single microalgae system. The results were further verified in continuous feeding photobioreactors and kept stable for 100 days. Metagenomic analysis revealed that the abundance of genes related to microalgae assimilation increased by 14 %-50 % in answer to photosynthesis and NH4+-N absorption, while that related to nitrification apparently dropped, indicating that MBS was a sustainable method capable of enhancing NH4+-N removal from REEs wastewater.


Assuntos
Microalgas , Águas Residuárias/microbiologia , Amônia , Simbiose , Desnitrificação , Nitrogênio/análise , Bactérias/genética , Biomassa
17.
Bioresour Technol ; 367: 128301, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36370937

RESUMO

Microalgae cannot meet the bait demand for aquaculture due to light intensity limitation and other disadvantageous conditions. This research selected 6 mixotrophic microalgae, and the optimal strains and organic carbon were screened. The results showed that Thalassiosira pseudonana and Chlorella sp. are suitable for mixotrophic culture. The maximum cell density of Thalassiosira pseudonana was found to be 1.67 times than that of the photoautotrophic group when glycerol was added. The maximum cell density of Chlorella sp. with acetic acid was 1.69 times than that of the photoautotrophic group. When the concentration of acetic acid was 5.0 g·L-1 and the concentration of KNO3 was 0.2 g·L-1, the maximum biomass of Chlorella sp. could reach 3.54 × 107 cells·mL-1; the maximum biomass of Thalassiosira pseudonana was 5.53 × 106 cells·mL-1 with 10.0 g·L-1 glycerol and 0.2 g·L-1 KNO3. Metabolomic analysis further revealed that mixotrophic bait microalgae could promote the accumulation of lipids and amino acids.


Assuntos
Chlorella , Microalgas , Microalgas/metabolismo , Biomassa , Chlorella/metabolismo , Carbono/metabolismo , Glicerol/metabolismo , Nutrientes , Acetatos/metabolismo
18.
Bioresour Technol ; 367: 128257, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36343781

RESUMO

Phycoremediation is gaining attention not only as a pollutant mitigation approach but also as one of the most cost-effective paths to achieve carbon neutrality. When compared to conventional treatment methods, phycoremediation is highly effective in removing noxious substances from wastewater and is inexpensive, eco-friendly, abundantly available, and has many other advantages. The process results in valuable bioproducts and bioenergy sources combined with pollutants capture, sequestration, and utilization. In this review, microalgae-based phycoremediation of various wastewaters for carbon neutrality and circular economy is analyzed scientometrically. Different mechanisms for pollutants removal and resource recovery from wastewaters are explained. Further, critical parameters that influence the engineering design and phycoremediation performance are described. A comprehensive knowledge map highlighting the microalgae potential to treat a variety of industrial effluents is also presented. Finally, challenges and future prospects for industrial implementation of phycoremediation towards carbon neutrality coupled with circular economy are discussed.


Assuntos
Poluentes Ambientais , Microalgas , Águas Residuárias , Carbono , Biomassa
19.
Bioresour Technol ; 367: 128270, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36347483

RESUMO

In this study, a novel method of coupling phytohormones with saline wastewater was proposed to drive efficient microalgal lipid production. All the six phytohormones effectively promoted microalgae growth in saline wastewater, and further increased the microalgal lipid content based on salt stress, so as to achieve a large increase in microalgal lipid productivity. Among the phytohormones used, abscisic acid had the most significant promoting effect. Under the synergistic effect of 20 g/L salt and 20 mg/L abscisic acid, the microalgal lipid productivity reached 3.7 times that of the control. Transcriptome analysis showed that differentially expressed genes (DEGs) of microalgae in saline wastewater were mainly up-regulated under the effects of phytohormones except brassinolide. Common DEGs analysis showed that phytohormones all regulated the expression of genes related to DNA repair and substance synthesis. In conclusion, synergistic effect of salt stress and phytohormones can greatly improve the microalgal lipid production efficiency.


Assuntos
Microalgas , Microalgas/metabolismo , Reguladores de Crescimento de Plantas , Águas Residuárias , Ácido Abscísico/metabolismo , Lipídeos , Estresse Salino , Biomassa
20.
Bioresour Technol ; 367: 128278, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36351535

RESUMO

In comparison to other methods of producing hydrogen, the production of biohydrogen is significantly less harmful to the surrounding ecosystem when it was produced from the biological origin such as microalgae. It could take the place of conventional fossil fuels while avoiding the emission of greenhouse gases. The substrates such as food, agricultural waste, and industrial waste can be readily utilized after the necessary pretreatment, led to an increase in the yield of hydrogen. Improving the production of biofuels at each stage can have a significant impact on the final results, making this method a potentially useful instrument. As a consequence of this, numerous approaches to pretreat the algal biomass, numerous types of enzymes and catalyst that play a crucial role for hydrogen production, the variables that influence the production of hydrogen, and the potential applications of genetic engineering have all been comprehensively covered in this study.


Assuntos
Hidrogênio , Microalgas , Biomassa , Ecossistema , Biocombustíveis
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